Evidence that fatty acyl CoA synthetase is a mediator of ischemia/reperfusion injury (I/R) in the rat

Decreased NO synthesis during ischemia is thought to facilitate surface expression of cell adhesion molecules such as pCAM, contributing to I/R injury. Earlier, we showed that Triacsin C (TriC), a long chain fatty acyl CoA synthetase inhibitor, increased NO release in cultured human and rat vascular endothelial cells and isolated rat aortic segments, leading us to hypothesize that TriC would increase NO and reduce leukocyte transmigration during experimental ischemia. Using the rat ischemic hind-limb model instrumented with NO probes (WPI Instruments), we measured the difference in NO concentration between the normoxic and ischemic limbs in TriC or vehicle treated animals.

The results are shown:

TreatmentControlIschemiaReperfusionVehicle0.54±2.1 nM−195±8.4 nM11 ± 7.5 nMTriC2.3±10 nM−83±4.3 nM * 130 ±3.1 nM *

Leukocyte adhesion, rolling and transmigration were evaluated by intravital microscopy in the rat mesenteric vasculature of TriC or vehicle treated animals. The results (leukocytes/min) are summarized:

Vehicle n = 3TriC n = 4Rollingt 0 13 ±311±2NSt 120 min 48±616±5p<0.001

Adhesiont 0 1±11±1NSt 120 min 9±13±1p<0.001Transmigrationt 0 1±11±1NSt 120 min 6±12±1p<0.001

These results strongly support our hypothesis, and suggest that long chain fatty acyl CoA synthetase is a key enzyme in governing eNOS activity during I/R.